Short term decisions and long-term responses of catchment systems
Nicholas Howden University of Bristol, UK
Tim Burt, Fred Worrall (Durham University, UK) Thorsten Wagener, Valentina Noacco (University of Bristol, UK) Helen Jarvie (Centre for Ecology and Hydrology, UK)
Tim Burt Fred Worrall Thorsten Wagener Valentina Noacco Helen Jarvie
2005 2006 2007 2008 2009 20100
5
10
15
con
cen
tra
tion
(m
g/l)
Dissolved Organic Carbon as C
2005 2006 2007 2008 2009 20100
5
10
15
co
nce
ntr
atio
n (
mg
/l)
Nitrate as N
2005 2006 2007 2008 2009 20100
5
10
15
con
ce
ntr
atio
n (
mg/l)
Total Phosphorus as P
2005 to 2010
1980 to 2010
1980 1985 1990 1995 2000 2005 20100
5
10
15
co
nce
ntr
atio
n (
mg
/l)
Nitrate as N
1980 1985 1990 1995 2000 2005 20100
5
10
15
con
cen
tra
tio
n (
mg/l)
Total Phosphorus as P
1980 1985 1990 1995 2000 2005 20100
5
10
15
con
cen
tra
tio
n (
mg/l)
Dissolved Organic Carbon as C
1950 1960 1970 1980 1990 2000 20100
5
10
15
co
nce
ntr
atio
n (
mg
/l)
Nitrate as N
1950 1960 1970 1980 1990 2000 20100
5
10
15
con
cen
tra
tio
n (
mg/l)
Total Phosphorus as P
1950 1960 1970 1980 1990 2000 20100
5
10
15
con
cen
tra
tio
n (
mg/l)
Dissolved Organic Carbon as C
1950 to 2010
1920 1930 1940 1950 1960 1970 1980 1990 2000 20100
5
10
15
co
nce
ntr
atio
n (
mg
/l)
Nitrate as N
1920 1930 1940 1950 1960 1970 1980 1990 2000 20100
5
10
15
con
cen
tra
tio
n (
mg/l)
Total Phosphorus as P
1920 1930 1940 1950 1960 1970 1980 1990 2000 20100
5
10
15
con
cen
tra
tio
n (
mg/l)
Dissolved Organic Carbon as C
1920 to 2010
1860 1870 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 20100
5
10
15
co
nce
ntr
atio
n (
mg
/l)
Nitrate as N
1860 1870 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 20100
5
10
15
con
cen
tra
tio
n (
mg/l)
Total Phosphorus as P
1860 1870 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 20100
5
10
15
con
cen
tra
tio
n (
mg/l)
Dissolved Organic Carbon as C
1860 to 2010
Howden NJK, TP Burt, SA Mathias, F Worrall, MJ Whelan [2011] Nitrate pollution in intensively farmed regions: What are the prospects for sustaining high-quality groundwater?, Water Resources Research, 47, W00L02, 10.1029/2011WR010843.
River Thames Catchment
1860 1870 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 20100
5
10
15
co
nce
ntr
atio
n (
mg
/l)
Nitrate as N
1860 1870 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 20100
5
10
15
con
cen
tra
tio
n (
mg/l)
Total Phosphorus as P
1860 1870 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 20100
5
10
15
con
cen
tra
tio
n (
mg/l)
Dissolved Organic Carbon as C
1860 to 2010
Annual land use records from 1867
Howden NJK, TP Burt, SA Mathias, F Worrall, MJ Whelan [2011] Modelling long-term diffuse nitrate pollution at the catchment-scale: Data, parameter and epistemic uncertainty, Journal of Hydrology, 403, 337-351, 10.1016/j.jhydrol.2011.04.012.
• parish land use
• annual records (MAFF68)
Howden NJK, TP Burt, F Worrall, SA Mathias, MJ Whelan [2013] Farming for Water Quality: Balancing Food Security and Nitrate Pollution in UK River Basins, Annals of the Association of American Geographers, 103(2), 397-407, http://dx.doi.org/10.1080/00045608.2013.754672.
Nitrogen Inputs
Model to estimate nitrogen available for leaching from inputs to land and water due to: animals, fertiliser, grassland ploughing, atmospheric deposition, fixation, crop uptake and wastewater discharge.
Howden NJK, TP Burt, F Worrall, SA Mathias, MJ Whelan [2013] Farming for Water Quality: Balancing Food Security and Nitrate Pollution in UK River Basins, Annals of the Association of American Geographers, 103(2), 397-407, http://dx.doi.org/10.1080/00045608.2013.754672.
Nitrogen Inputs (a)
1870 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000
tota
l N
-lo
ad
ing
(kg
/ h
a)
0
20
40
60
80
100
120
140
Total load
(b)
1880 1900 1920 1940 1960 1980 2000
pro
po
rtio
n o
f to
tal lo
ad
0.0
0.2
0.4
0.6
0.8
1.0
fertiliser
animals
ploughing
fixation
deposition
Nitrogen Model
0 10 20 30 40 50 600
0.002
0.004
0.006
0.008
0.01
0.012
0.014
time (years)
rela
tive c
on
ce
ntr
atio
n (
C / C
0)
Howden NJK, TP Burt, F Worrall, SA Mathias, MJ Whelan [2011] Nitrate pollution in intensively farmed regions: What are the prospects for sustaining high-quality groundwater?, Water Resources Research, 47, W00L02, 10.1029/2011WR010843.
1940 1950 1960 1970 1980 1990 2000 20100
5
10
15
20
25
30Agriculture Inputs
kto
nn
es P
per
ye
ar
1940 1950 1960 1970 1980 1990 2000 20100
0.5
1
1.5
2
2.5
3
3.5
4Effluent Inputs
kto
nn
es P
per
ye
ar
urine
faeces
food waste
detergent
mains water
arable fertiliser
grassland fertiliser
cattle
sheep
Phosphorus Inputs
Howden NJK, TP Burt, F Worrall, HP Jarvie [in prep.] Phosphorus concentrations and fluxes in the River Thames catchment 1936 to 2014, Science of the Total Environment (Special Issue on Macronutrient Cycles), 2016.
Phosphorus Inputs and Output
Howden NJK, TP Burt, F Worrall, HP Jarvie [in prep.] Phosphorus concentrations and fluxes in the River Thames catchment 1936 to 2014, Science of the Total Environment (Special Issue on Macronutrient Cycles), 2016.
1940 1950 1960 1970 1980 1990 2000 20100
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
kto
nn
es P
per
ye
ar
Net effluent contribution
0
1
2
3
4
5
6
7
8
9
10
co
nce
ntr
ati
on
(m
g P
/l)
Phosphorus Inputs and Output: the Legacy?
Haygarth PM, HP Jarvie, SM Powers, AN Sharpley, JJ Elser, J Shen, HM Peterson, N-I Chan, NJK Howden, TP Burt, F Worrall, F Zhang, X Liu [2014] Sustainable Phosphorus Management and the Need for a Long-Term Perspective: The Legacy Hypothesis, Environmental Science and Technology, 48, 8417-8419, 10.1021/es502852s.
Conclusions… to date…
• Nitrate – animal, fertiliser and ploughing inputs important, and almost 60% of
response controlled by long-term groundwater processes with a lag time of >30 years
– if we reduce inputs by 50% now, the immediate effect would be a 20% reduction in outputs…
• Phosphorus – wastewater inputs have risen steadily and then declined after WWTD,
but there is a large legacy store of P; diffuse inputs to land do not appear to have a fluvial impact?
• Ongoing work: how do these results map to wider scales?
National-Scale Models of N, C and P Export (1 km2)
Worrall et al. [2012] - STOTEN Worrall et al. [2012] -JoH Worrall et al. [in prep]
Worrall F, H Davies, TP Burt, Howden NJK, MJ Whelan, A Bhogal, A Lilly [2012] The flux of dissolved nitrogen from the UK – Evaluating the role of soils and land-use, Science of the Total Environment, 434, 90-100, 10.1016/j.scitotenv.2012.01.035.
1860 1870 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 20100
5
10
15
co
nce
ntr
atio
n (
mg
/l)
Nitrate as N
1860 1870 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 20100
5
10
15
con
cen
tra
tio
n (
mg/l)
Total Phosphorus as P
1860 1870 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 20100
5
10
15
con
cen
tra
tio
n (
mg/l)
Dissolved Organic Carbon as C
Howden NJK, TP Burt, F Worrall, SA Mathias, MJ Whelan [2011] Nitrate pollution in intensively farmed regions: What are the prospects for sustaining high-quality groundwater?, Water Resources Research, 47, W00L02, 10.1029/2011WR010843.
Nitrogen Inputs and Outputs